If you're asking because you're wondering how bad the latency is, remember that microwave is the speed of light and the most direct route between two points. It'll be better than fiber, all other things being equal. It's possible the bandwidth isn't up to snuff, but latency shouldn't be a problem.
I'm guessing these microwave links are short enough to blast through poor atmospheric conditions that are very common in a place like Seattle. At greater distances from the provider packet loss (resulting latency problems) could be a legitimate concern.
PING google.com (173.194.33.165) 56(84) bytes of data.
64 bytes from sea09s18-in-f5.1e100.net (173.194.33.165): icmp_req=1 ttl=59 time=0.857 ms
64 bytes from sea09s18-in-f5.1e100.net (173.194.33.165): icmp_req=2 ttl=59 time=0.779 ms
64 bytes from sea09s18-in-f5.1e100.net (173.194.33.165): icmp_req=3 ttl=59 time=0.831 ms